According to the Telegraph, LifeGem obtained the sample of the composer's locks from the University Archives in Connecticut, which boasts barnet samples from a raft of celebs including Albert Einstein, Abraham Lincoln and Napoleon.

Experts at LifeGem's Chicago HQ burned the hair without oxygen to ensure it didn't disintegrate, then extracted 130 milligrammes of carbon destined for three separate diamonds formed by heating the material to very high temperatures and then pressing it for two weeks.

One of the resulting "Round Brilliant" gems will go to the University Archives, LifeGem will keep another, while the third will be auctioned for the benefit of various charities including the UK's Dreams Come True, an organisation which "fulfils the wishes of terminally and seriously ill children".

David Hampson, chief exec of LifeGem UK, said: "The proceeds of this historical diamond will give us the opportunity to help a great number of children. But it also highlights the the new technology that enables us to make a diamond from a lock of hair. In the past we have only been able to make diamonds from a person's ashes. But now people are given the opportunity to give a gift as a celebration of life."

Regarding the estimated £500k price tag, Hampson added: "We are hoping that perhaps a high profile musician such as Sir Elton John or Sir Paul McCartney will buy it. But with it being on eBay, anyone can bid on it." They can indeed, for a starting bid in excess of $50k. ®